1. Field of the Invention
The present invention relates to imaging of multiphase flow in conduits, and more particularly to flow regime identification by face recognition and Bayesian classification of multiphase flows of oil, water (brine) and gas in flow conduits.
2. Description of the Related Art
Fluid imaging of flow tends to focus in general on the imaging of two phases. The technique generally used for two phase flow reconstruction has been based upon what is known as the filtered back projection algorithm. This type of flow reconstruction is described for example by Kak, Avinash C., Slaney, Malcolm “Principles of Computerized Fluid transit Imaging,” IEEE Press, New York, USA (1988), and Murrell, H. “Computer-Aided Tomography,” The Mathematical J. V6 (1996), pp. 60-65.
However, because of the nature of the fluids present in production of oil and gas, it is necessary to form images of three phase flow in conduits involved in hydrocarbon production. Because of the different fluid properties of water (brine), oil and gas it is difficult to address all three sets of fluids simultaneously. In the case of oil-water or water-oil multiphase flows, the medium has been utilized. In the case of liquid-gas or gas-liquid flows (where the liquid is brine or oil or both) an attenuation approach has been utilized. As far as is known, neither method, however, has provided a wholly satisfactory identification or recognition of a three phase multiphase flow cross section.
One type of flow regime where identification is observed to be least accurate has been occurring when there are high levels of free gas within the conduit system. Such levels of free gas cause multiple reflections. Since tomography generally relies on transmission rather than more complex reflections, the presence of gas bubbles or large amounts of free gas can result in clutter and multiple reflections which impede flow regime identification based on tomographic reconstruction. Flow regime identification in conduit systems is also proving difficult where there were other challenging measurement conditions, such as wet gas or saturated bubbly flow.